Global ChangeIntersection of Nature and Culture

In defense of sustainable meat production

Saturday, October 31st, 2009

Nicolette Niman has a column today in the NY Times, “Carnivore’s Dilemma,” in which she argues that meat production, especially beef, has gotten a bad rap because of its climate change impacts.  However, as she points out, not all meat production is the same in terms of its greenhouse gas production, similar to an earlier post that not all conventional farming is alike.

Niman’s family runs a livestock ranch network that is more humane and sustainable than your typical factory farm (you might be familiar with their pork products).  They have been featured in recent analyses of food ethics by Peter Singer.

She makes a number of good points, showing how conventional meat production contributes to climate change in ways that sustainable livestock farming doesn’t:

• land clearing to make way for pastures or crops to feed livestock
• enteric (gut) fermentation of feed grains that animals are not used to eating, causing the overproduction of methane
• feed grains that are often grown with fertilizers and pesticides using heavy machinery burning fossil fuels, which are energy and carbon intensive and lead to other ecological issues such as toxicity and nutrient pollution
• large manure piles or lagoons that emit other kinds of greenhouse gases like nitrous oxide.
• long supply chains and several processing steps that add energy

I think most people would agree that switching from an industrial mode of meat production to locally grown, more-organic, free-range modes of production is a good thing.   If all livestock animals were raised and killed humanely, raised on healthy, locally sourced foods, and sold with minimal processing and transportation, this would be a large step forward in terms of reducing both climate warming and animal cruelty (warning: this video is graphic).

Nevertheless, a conversation about food, global change, and sustainability should have acknowledged major challenges with animal-based food systems—even ones that are more sustainable:

• Meat eating is land intensive.  Why?  A farmer can raise more calories on a hectare of land by growing plants rather than animals.  This occurs for two reasons: (1) Livestock lose a lot of energy to the environment from their own metabolism (cellular respiration) to keep themselves alive.  Thus, a lot of the energy consumed in feed simply burns off to the environment rather being turned into a useful form that people can consume. (2) There are many parts of animals that we do not consume or digest (bones, hair, some organs, etc).  When you add both of these together, it turns out to be a significant loss of energy.   A field of plant crops also faces these issues—plants lose energy from heat and metabolism, and there is a lot of plant biomass we can’t eat or digest.  However, by eating animals (a two-level food chain), we encounter these lost sources of energy twice (once with the plants and again with the livestock), whereas we only encounter them once by eating only plants.  This means we lose less energy by eating plants compared to eating animals.   Put another way, we capture more energy in plant foods and can feed a greater number of people on a given land area.  In a world with rising human populations and affluence, which often translates to increased per-capita meat consumption, this means that there will be increasing pressure on land use for the production of meat.
• She advocates the benefits of pasture-raised animals.  But where are the pastures going to come from?  Modern factory farming fosters the illusion of being land efficient by growing animals in concentrated feedlots.  However, these animals are subsidized by a large fraction of land use to grow grains.  This estimate suggests that 60% of the U.S. corn supply is fed to livestock.  That’s a lot of land.  If we eliminated all factory farming and raised all livestock on pasture, we would need to use much of the land currently being used to grow corn, assuming that meat consumption levels remain constant.  Sure, that might not lead to a net increase in agricultural area, but it still represents a significant use of agricultural land.  The opportunity cost is being able to produce more calories from that land, which will likely be needed to feed more people in a future world of 9 billion. Therefore, sustainability, writ large, is going to require a shift away from meat-based diets and not just a shift from factory farming to sustainable livestock production.
• As Michael Pollan and others have pointed out, factory farms raise animals on grain and hormone supplements to make them develop quickly and move to market in half the time.  If we get rid of these things, our rate of livestock production may be cut by up to 50%.  If meat consumption remains steady, this means we may actually need to double the pasture area needed, which could lead to new land clearing.

Sustainable meat production is a good step forward, but it’s potentially more complicated with respect to global change than Niman portrays it.

Related post: Are conventional farmers always conventional?

photo credit:  http://www.flickr.com/photos/kwerfeldein/ / CC BY-NC-ND 2.0

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